The invention relates to a punching tool, in particular for green sheets.
It is often necessary, in still-unfired sheetlike ceramic substrates (green sheets), to punch holes in a certain pattern for one or more components or through-contacting means, before the substrate is further processed, for instance into supports for electronic components and conductor tracks. For that purpose, the punching tool has an upper tool that is provided with dies and a lower tool that has a cutting plate. The cutting plate has a flat top side, in which the holes to be punched are located at the intended points. With this arrangement, it is possible to produce components with a punched grid that is replicable. Depending on the feeding of the green sheet, it is possible with one and the same tool to create different punched patterns or components. Below the cutting plate, there is an air distributor plate and a vacuum plate, which mechanically support the cutting plate and supply the required media. For instance, the punched holes of the cutting plate must be subjected to compressed air, in order to blow punching waste (so-called slugs) out of the punched hole. Openings are also provided in the cutting plate and are subjected to compressed air, for guiding the green sheet on an air cushion. The feeding of the green sheet is thus reinforced. The disposition of the openings, like the disposition of the punched openings, is dependent on the pattern to be punched into the green sheet; that is, it is workpiece-specific or component-dependent. Accordingly, the embodiment of the vacuum plate which brings the media to the cutting plate is also workpiece-dependent. The vacuum plate is in turn supported by a lower tool base plate. The lower tool base plate is adapted to the workpiece-specific vacuum plate.
If a machine is to be converted from one workpiece or component (green sheet) to another workpiece, with a different punching grid, then the entire punching tool is replaced. If a component with a new punching grid is to be punched, then the entire tool is constructed from scratch.